Process for recovering butter from buttermilk



Patente'd s. 11, 1928.

UNITE STATES Ana-nun 1.. ausa'ron,

PATENT OFFICE, I

LANE, OI WABKINGTON, DISTRICT OF COLUMBIA.

roa momma Burma raon sur'rnniunx.

This "invention relates to an improved roc'ess for recovering butter or butterfat rom buttermilk or buttermilk whey derived from sour cream, and consists in passing such buttermilk or buttermilk whey through a centrifugal separator in which the-liquid is r d to centrifugal action for a' much longer period of time than is found necessary for whole milk. A creamy substance is ob-.

tained by this operation, which may be termed,

h ticles of casein that it as hitherto been ound impossible to efiect an efficient separation in the ordinary manner. Moreover, it is well known that the casein content of sour cream buttermilk precipitates easily. Attempts to separate butterfat from buttermilk result in the separator becoming rapidly clo ged by the filling up of the pathways throug the discs through which the buttermilk is distributed When these between the. various discs. 10 athways are completely clogged, no more uttermilk can pass through and separation ceases.

In order to avoid this clogging action, I

have devised a means which allows the sepa- I 56 rator to operateefiiciently for a great deal longer time than with the Ordinary cream separator, before complete clogging takes place and separation ceases. According to this feature of my invention, the pathways of the buttermilk through the discs are kept open for a much longer time by piercing the cover over the top disc of the separator with holes of approximately one-sixteenth inch diameter, preferably four in number, each 5 hole being located directly over the correspondin pathway of the milk through the discs. ese holes permit a small percentage of the buttermilk to escape throug the sepator into the skim milk, but serve to kee open 60 the pathways of the remainder of the uttermilk so that a great deal more buttermilk Application am September 22,1927. Serial 0,222,945,

may be separated before complete clog 'ng takes place and separation'ceases. wit out this invention, the se arator can be operated in treating buttermi k for only so short a time before separation ceases that separation n a commercial, practical way would be much less profitable, if at all.

I find that in sour cream buttermilk certain of the globules of butterfat are so enmeshed in casein that their specific gravity is reater than that of buttermilk and the glo ules are so very minute that they are therefore unrecoverable inthe form of cream or thin milk by'centrifugal force. The ror 0mm nnnnnsn, assrcmoa or oim-nm To nun'son n. a

centage of unrecoverable fat varies in di er-' ent lots, but is estimated at seventy-four per 7 cent of thetotal butterfat in the sour cream buttermilk. The remaining twenty-six per centof the total butter-fat in the sour cream buttermilk may be recovered by this invention in the form of cream of any desired 7 practical percentage of butterfat. a In order to-make the separation of butterfat from buttermilk commercially practica ble, I find that-it is desirable to eliminate at once the unseparable butterfat. This is accomplished; by passing the, buttermilk through a centrifugal separator at approxim'ately-the rate of inflow used for whole milk. With the untreated sour cream buttermilk testing on an avera e of sixty hundredths per cent butterfat,th1s resultsin the recovery from v the cream outlet of approximately thirty per cent of the volume of the original buttermilk and testing approximately eighty hundredths per cent butterfat, or about forty per cent of the butterfat in the original sour cream buttermilk is obtained through the cream outlet in the form of a'butte rmilk testing about eighty hundredths per cent butterfat. This may be termed the primary, separation and consists in dividing the butterfat into separable and non-separable ortions. About twenty-six percent of the utterfat content of the original sour cream buttermilk can be recovered bypassing the thin milk obtained from the cream spout in the primary separation through a secondary separation in which the liquid is exposedto the centrifugal force of the separator for from-six to twenty times as long as is requiredfor eflicient se ration of the whole milk, depending on t e per cent of fat desiredin the cream;

It has been im ossible heretofore to pass suflicient quantities of buttermilk through the separator before complete clogging took place and separation ceased. By the means of the holes drilled in the cover over the discs directly over the pathways of the milk through the discs the time of the separators eflicient operation is more than doubled.

It has heretofore been found im ossible to convert the thin buttermilk obtained from the cream outlet into cream of reasonable density for churning purposes without a loss of a greater part of thebutterfat.

I 11nd, however, that if this thin buttermilk is exposed for a considerably longer period of time, i. e., from six to twenty times that required for whole milk, to the centrifugal force exerted by the separator that the percentage of butterfat recovered 18 very greatly increased. The density of the cream, obtained varies directly with the length of,

time it has been exposed to the action of centrifugal force in the separator. This is probabl due to the much smaller size of the fat 10 ules in buttermilk as compared to the at lobules in whole milkand to an increase in t e specific gravity of the globules due to the adherence of a small amount of casein. Thepurpose of the centrifugal se arator is,- of course, to separate liquids of di crent specific gravities. In the case of whole milk, this is readil accomplished byexposing whole milk to t e centrifugal force of the separator for a proximately a minute or less. This perio of exposure separates the cream, from the skim milk very efficiently. However, to separate cream from buttermilk requires from six to twenty times as long as for whole milk, depending uponthe percentage offat desired in the cream- 'i r In actual operation, aqpan'tity of sour. cream buttermilk is passed t rough a centrifugal separator at practically the rated inflow for whole milk. The cream screw is set. to deliver approximately one fourth of the buttermilk passed through the separator in the formof a thin milk testing about eighty hundredths per cent butterfat as compared to about fift -five hundredths per cent in the buttermilk rom the skim outlet, based on a fat content of sixtyhundredths per cent in.

the sour cream buttermilk. This process, the

primary separation, separates the fat globules of low specific gravity from those of higher specific ravity that are robabl unchurnable, due to adhering and y casein. Y r

The thin milk obtained from the cream spout in the primary separation is next assed through the centrifugal separator at rom one sixth to one twentieth the normal rated inflow for whole milk. The continued enveloping than that employed in treating whole milk.

exposure to centrifu al force graduall concentrates the globules of butterfat mto a cream herein termed buttermilk cream, the

fat content of which varies with the time of exposure to the centrifugal force of the sepa- 7 rator. The cream obtained from the cream spout in this separation, referred to as the secondaly separation, is of good qualityaml..."

may be then churned into a reasonably good quality of butter. i II By this process, approximately twenty-six per cent of the butterfat content of sour cream buttermilk may be obtained atthe end of the secondary separation in the form of cream testing 20%. or more butterfat, as comab pared to less than two percent of cream testng-over twenty percent if the rated inflow for whole milk is used for either rimary or secondary separations or both. makes possible the commercial and profitable re M covery of valuable butterfat as cream from sour cream buttermilk.

What Iclaim isz- '1. A substantially continuous rocess for treating sour cream buttermilk or uttermilk 9 ging in a subsequent centrifugal treatment 9 and thensubjectmg the product to a centrifugal force for a substantially longer period of time than that which is necessary for whole milk separation. a

2. A substantially continuous rocessfor treating sour cream buttermilk or uttermilk whey to recover aportion of the butter fat thereof, which consists in subjecting sour cream buttermilk or buttermilk whey to I preliminary treatment for preventing clogging in a sub uent centrifugal treatment and then subjecting the product to a centrifugal force for a period a pi'oximately six to twenty times that whic is nry. for whole milk separation. r

3. A process for treating sour cream buttermilk or buttermilk whey to recover a-portion of the-butter fat thereof, which consists in effecting a primary separation to se arate the recoverable from the non-recoverable fat portions, the primary separationconsisting 111 passing the butter milk or buttermilk whey through a centrifugal separator at approximately the same rate used forseparting the cream from whole milk, recoverin the fluid emerging from the cream outlet 0 the sepae rator, then effecting a seconda separation by passing such recovered flui through a cream separator at a substantially less rate 4. A process for treatingsour cream buttermilk or buttermilk whey to recover a portion of the butter fat thereof, which consists in effecting a primary separation to separate the recoverable from the non-recoverable fat Ill) 1n passing the uttermilk or buttermilk whey through a centrifgual se arator at a proximately the same rate use for separating the cream from whole milk, recoverin the fluid emerging from the cream outlet 0% the separator, then effecting a seconda separatlon by passing such recovered fiui g through ;a

cream separator at a substantially less rate than that em loyed in treating whole milk, m recoverin uttermilk' cream from the cream out et, then churning said buttermilk cream to obtain butter. i

X In testimonyt'whereof I aflix my signature v L. RUSHTOYNQV 

